1. Field of the Invention
The present invention relates to a motor vehicle having an improved coupling structure for a speedometer cable.
2. Description of the Relevant Art
Speedometer cables in motor vehicles are generally coupled to gear cases mounted adjacent to axles.
For example, Japanese Utility Model Publication No. 44(1969)-22938 discloses a speedometer cable coupling construction including a gear case mounted on the hub of an axle and a worm wheel mounted in the gear case and rotatable with the axle. One end of a speedometer cable is connected to a worm wheel disposed in the gear case and held in mesh with the worm wheel. Where this cable coupling mechanism is incorporated in a four-wheel motor vehicle with front wheels driven by the engine, the speedometer cable is operatively coupled to the axle of one front wheel. However, the speedometer cable thus coupled is poor in durability since it is twisted each time the front wheel is steered. In addition, the actual layout of the speedometer cable is not easy to carry out. On four-wheel motor vehicles with engine-driven rear wheels or motorcycles, the speedometer cable is operatively coupled to the axle of the rear wheel. The problem of this speedometer cable coupling structure is that speed indication errors are large inasmuch as the cable is required to be relatively long.
Japanese Laid-Open Patent Publication No. 57 (1982)-167884 discloses a power unit assembly in which a driver bevel gear is formed on an outer end of the output shaft of a power unit or a gear transmission, and a final output shaft is mounted on one side of a power unit case and has a driven bevel gear meshing with the driver bevel gear. The final output shaft is coupled to a propeller shaft which transmits engine power to the axle of a rear wheel.
The inventors have made the present invention in order to solve the drawbacks of the conventional speedometer cable coupling mechanisms based on the power unit structure disclosed by the latter publication.